Hardcoat Anodizing, often called "Type III anodizing" as denoted by the MIL-A-8625 specification, is an electrochemical process that creates a controlled oxide film on the surface of aluminum. Hardcoat Anodizing utilizes sulfuric acid, low bath temperatures, and constant current rectification to achieve a very hard coating (60-70 Rockwell C). Hardcoat Anodizing is generally used for applications that need a corrosion, abrasion, and wear resistant coating. The appearance of the coating ranges from light to dark gray, depending on the alloy makeup of the aluminum substrate, and it can also be dyed black. Parts can be processed with multiple finishes, such as Hard Coat/Chem Film or Hard Coat/Electroless Nickel Plating.
+ Class 1, Natural
+ Class 2, color
Slik-Seal with PTFE per MIL-A-63576, TYPE I
+ Tuff-Kote with PTFE per MIL-A-63576, TYPE III
- Compatible with adhesives
- Excellent lubricity
- Resistant to marine and atmospheric corrosion
- High operating temperatures
- Electrically resistant
- Galvanic neutrality (prevents galvanic corrosion from interaction between dissimilar metals)
There are hundreds of governmental, industrial, and commercial anodizing specifications in use, each with their own method of specifications for coating, seals, dyes, etc. Any anodizer should recognize the Type II designation to indicate a sulfuric anodize, Class 1 to specify natural color or no dye, and Class 2 to indicate a dye. This anodizing meets Mil-A-8625.
Sulfuric anodizing is rather tolerant of aluminum alloys for anodizing with the exception of high-silicon die-cast alloys such as 380. The less alloying elements there are the higher the clarity and depth of color of the anodize coating.
Elite Metal Finishing can provide a wide variety of colors. Some colors include clear anodizing, black, red, blue, and gold. If you have a special color to match, call us for professional assistance.